In preliminary experiments it was found that nickel and chromate induce the formation of stable ternary complexes of DNA-metal and protein. We intend to utilize the formation of these complexes as a basis for detecting exposure to toxic agents. The DNA-protein complexes will be studied in detail in rats treated with NiCl2 and K2CrO4. Polyclonal antibodies to proteins crosslinked to the DNA by nickel and chromate will be developed in rabbits. Antisera will also be developed to proteins complexed to the DNA by UV. These antibodies will be utilized to detect DNA-protein complexes in rat lymphocytes following in vivo exposure to the metals, as well as to several other chemical agents including methylmercury, chloroform, CdCl2 and benzene. The detection of DNA- protein complexes induced by these metals will be performed utilizing gel electrophoresis and western blotting. Additionally, a simplified radioimmune assay will be developed to detect DNA-protein complexing. If the results from the rat experiments prove promising, similar studies will be performed with human lymphocytes in vitro. Eventually, studies of humans exposed to these chemical agents will be initiated. Finally, to attempt to develop more efficient ways of detecting protein antigens complexed to DNA and to investigate whether detection of chemical- specific DNA-protein complexes can be achieved, monoclonal antibodies will be developed to DNA-protein complexes induced by each of the chemical agents.